1. Field of the Invention
The present invention relates to microprocessors and more particularly to a method and apparatus for loading the program sequence into a microprocessor memory.
2. Description of the Prior Art
Microprocessors, unlike large general purpose computers, normally do not include a compiler which will translate instructions coded in a language comprehensible to a user into the necessary machine language instructions. Thus, a programmer who directs his efforts to programming a microprocessor must necessarily memorize a list of machine code instructions and since such instructions are normally in binary form, there is no convenient way of identifying an erroneous instruction. Furthermore, should a programmer desire to modify an existing program he, again, is faced with a program coded strictly in machine code and, because of the lack of an immediate comprehensive identification of the various code words in the instruction chain, such user very often prefers to start fresh with each new program. To reduce somewhat this frequent redundancy it has been typically practiced in the microprocessing art to segment such programs into standard instruction sequences or subroutines where each subroutine may be stored on a precoded ROM and only the connecting instructions are therefore modifiable. This manner of implementation greatly reduces the efficiency of any programming sequence since by connecting such standard instruction sets, steps often trivial or redundant to the overall program requirements, must be sequenced through during the execution of the program.
Generally a microprocessor offers advantages in cost to the user and is therefore purchased separately from a printing facility. If and when a print-out is desired, either a time-shared printer or a remote printer is brought in and any program instructions are thus listed out. Furthermore, the cost considerations of a microprocessor also dictate relatively limited storage space and therefore render any compiler functions prohibitive. Thus, the required translation into comprehensible instructions is not typically available to a typical user of a microprocessor.